1. Technical Field
The disclosure relates to an inkjet printer configured to perform printing by ejecting ink from an inkjet head.
2. Related Art
In an inkjet printer described in Japanese Unexamined Patent Application Publication No. 2009-269313, ejecting ink from an inkjet head generates ink mist which is atomized ink. The ink mist contaminates the inside of the printer. Accordingly, it is desirable to reduce the ink mist.
When multiple ink drops are ejected for one pixel, an air flow (self-generated air flow) generated by the flying ink drops and flowing from a nozzle to a sheet is strong, and fine droplets are less likely to scatter. Accordingly, the amount of ink mist generated is relatively small. Meanwhile, when one drop is ejected, the self-generated air flow is weaker than that in the case where multiple drops are ejected, and fine droplets are more likely to scatter. Accordingly, the amount of ink mist tends to be great. Hence, in order to reduce the ink mist, it is effective to perform no ejection of one drop for one pixel.
However, when the ejection of one drop is simply omitted, the number of gradation steps is reduced and print image quality decreases. Meanwhile, when the printing is performed with the number of drops changed such that the ejection of one drop is omitted but the number of gradation steps is maintained, the ink mist can be reduced with the decrease in print image quality suppressed.
Specifically, for example, when there are four levels of 0, 1, 2, and 3 for the number of drops for each pixel in the image data, printing is performed with these four levels changed to four levels of 0, 2, 3, and 4 by incrementing the number of drops of 1 to 3 by one. The ejection of one drop is thereby eliminated with the four gradation steps maintained.